1. Field of the Invention
The present invention relates generally to sorting apparatus having an adjustable gauging strip spaced above a portion of a rotating disk. More specifically the present invention relates to an apparatus used to sort marine crustacean, or other delicate objects, by sequentially passing such objects through a series of gauging operations.
2. Background of the Prior Art
Today as in the past, shrimp are sorted by hand. Hand sorting is expensive and slow. A number of devices have been developed to mechanically sort live shrimp, but none of them has achieved any significant degree of commercial success. This lack of commercial success reflects the prior arts failure to teach a device that is capable of successfully sorting live shrimp.
For example, U.S. Pat. No. 2,989,180 describes a shrimp sorter that operates by passing shrimp down a channel between a plurality of elongated rollers having stepped peripheral surfaces. This device is impractical for two reasons. First it is mechanically complex and expensive. Second, and more important, live and freshly killed shrimp are mechanically delicate. Specifically, they are easily damaged by premature separation of their head portion. Any device using rotating rollers as a gauging means will cause the shrimp's head to be pinched off. The headless shrimp is then missorted, which defeats the object of the invention.
Hand sorting, aside from being dull, monotonous and low-paying work, has a number of inherent and serious disadvantages.
Being slow, hand sorting of large catches cannot be done at sea. This means the entire catch must be brought to shore for sorting. Much of the catch may die in route. Additionally many shrimp caught are too small for commercial use, these are removed and thrown out rather than being returned to the sea to mature for a later harvest.
Because the work is dull and monotonous it is often done poorly.
Finally, shrimp is best when it is fresh. Even the best hand sorting produces shrimp that have been dead for a considerable period of time prior to freezing. Significant market demand exists for large perfect "heads on" shrimp. These shrimp must be fresh frozen while they are alive just after being caught. This demand cannot be satisfied at present because the shrimp's head portion turns a dark color immediately after death. Keeping the shrimp alive or hand sorting them at sea is economically unrealistic.
It is therefore an object of the present invention to provide an apparatus capable of meeting the long known need for rapid and efficient mechanical sorting of shrimp.
A further object of the present invention is to provide a mechanical shrimp sorter capable of being operated at sea on board a shrimp boat as well as in a fixed plant on land.
Still another object of the present invention is to provide a mechanical shrimp sorter capable of accurately sorting either heads on shrimp or tails only shrimp.
Yet a further object of the present invention is to provide a shrimp sorter capable of operating at sea to return to the sea alive all shrimp that are too small to be commercially valuable.
A final object of the present invention is to provide a sorting apparatus that can be gauged in series and/or in parallel to provide for additional thru-put and a plurality of grades output.